Perfect, I was able to see the errors in your accounts. Since it's listed as an API error that's something that eBay sent us back. So the message "Tax Datasource is currently unavailable" I would assume is some problem on their end.
I would just try listing the items again.
Sellers using eBay tools are getting the same error:
http://www.blackthornesw.com/discus/messages/5259/38575...1174878800#POST84909An eBay employee John Slocum said it looks to be an eBay problem.